Marin County probes 2 cases of rare brain disease

The Marin County Health Department says that mad cow disease is not to blame for the death of 59-year-old woman from San Rafael.

The new information came out on Thursday around 4 p.m. The Marin County Public Health Department said at this time, they have excluded they type related to mad cow disease in one of the two cases being investigated. This comes after tests were done at a national lab.

Aline Shaw died on Jan. 27. The Marin County Department of Health and Human Services began looking into a possible connection with a rare form of Creutzfeldt-Jakob disease, also known as CJD. But in a statement, the county's public health officer, Craig Lindquist, M.D., said, "We have no evidence of any environmental or public health risk in Marin County."

It appears Shaw still died of CJD, but not the variant kind which is extremely rare. There are two kinds of CJD as explained to us by Michael Geschwind, M.D., of UCSF.

"The variant form of CJD is linked to an animal form known as Bovine spongiform encephalopathy, or BSE, which is more commonly known as mad cow disease. In the sporadic form of the disease, it's not linked to any animal diseases," said Geschwind.

The sporadic variety affects one in a million people. Variant CJD, linked to mad cow disease, killed about 175 people in the UK in the early 1990s after eating tainted beef. Both kinds of CJD -- variant and sporadic -- are caused by a protein known as prion, triggering severe dementia and death. Researchers at UCSF's Small Molecule Discovery Center continue to study how the protein affects the brain.

The scientific community believes it would be nearly impossible for cows in the U.S. to become infected.

"We have very strict import regulations to keep possible positive animals out of the United States from countries that have it and we've have had a very effect feed ban in place for many years that stops the transmission of the disease," said Breitmeyer.

Shaw was the executive director of LITA (Love is the Answer) -- a non-profit providing companionship for elderly people. Gerrda Focardi is a volunteer.

"In our last conversation she asked, 'Will LITA be all right?' and that was just a few days before she wasn't able to speak anymore," said Focardi.

Shaw had been their director of LITA for seven years. With regard to the other reported case, the Marin County Health Department says it is still under investigation and will update the public as the information becomes available.

The disease is not contagious between people.

A second person in Marin County has also been diagnosed with the disease, but officials say there is nothing to suggest a public health risk.